Trucks equipped with electronic driver logs have significantly lower crash rates than those without, according to a Federal Motor Carrier Safety Administration test.

The test found that the ELD-equipped trucks had an 11.7% lower crash rate and a 5.1% lower preventable crash rate, the agency said.

They also had a 53% lower rate for hours-of-service driving violations, and a 49% lower rate for non-driving violations.

“The results show a clear safety benefit, in terms of crash and HOS violation reductions, for trucks equipped with Electronic Hours-of-Service Recorders,” the agency said.

The study looked at Class 7 and 8 trucks from 11 carriers and is skewed toward larger, for-hire fleets and may not represent the entire industry, the agency said.

The study will be posted Monday on the docket where all of the agency’s electronic logging material is kept, including the proposed rule that will mandate near-universal use of electronic logs.

The docket remains open for comments until May 27, although that deadline may be extended. The Commercial Vehicle Safety Alliance, representing state police and other enforcement interests, has asked the agency for a one-month extension.

“This is a complex and significant rulemaking,” said CVSA Executive Director Stephen Keppler.

He said CVSA needs more time to understand the technology options in the proposal, and states need more time to evaluate its impact in the field.

In a related development, the agency said it needs to clarify the rules for Automatic On-Board Recording Devices, the older automated logging systems that some fleets have used for decades.

The agency said that some inspectors have been asking drivers to give them printouts from these devices, and in some instances have issued citations because the devices did not display certain information.

But the rules have never required these devices to print out logs, although drivers can volunteer a printout if the device has that capability. Inspectors can request the driver to send additional information via email or fax within 48 hours.